Light-emitting device and electronic apparatus

0001This is a Continuation of application Ser. No. 11,548,802 filed Oct. 12, 2006. The disclosure of the prior application is hereby incorporated by reference herein in its entirety.

CROSS-REFERENCE TO RELATED APPLICATION

0002The present application claims priority from Japanese Patent Application No. 2005-345299, filed in the Japanese Patent Office on Nov. 30, 2005, the entire disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

00031. Technical Field

0004The present invention relates to a structure of a light-emitting device utilizing a light-emitting material, such as an organic electroluminescent (EL) material.

00052. Related Art

0006As one type of active matrix light-emitting device, a structure in which a transistor that controls a current to be supplied to a light-emitting element (such a transistor is hereinafter referred to as a “drive transistor”) is provided for each light-emitting element is known. Another type of active matrix-light emitting device is disclosed in U.S. Pat. No. 6,229,506 (FIG. 2) and JP-A-2004-133240 (FIGS. 2 and 3). In this structure, a transistor that compensates for errors of the threshold voltage of a drive transistor (such a transistor is hereinafter referred to as an “initializing transistor”) is disposed between the gate electrode and the drain electrode (or source electrode) of the drive transistor. In this structure, when the initializing transistor is turned ON to allow the drive transistor to be diode-connected, the gate electrode of the drive transistor is set to be a potential corresponding to the threshold voltage. In this state, the gate electrode of the drive transistor is changed to a potential in accordance with a desired grayscale level. Then, a current which is not influenced by the threshold voltage can be supplied to the corresponding light-emitting element.

0007The above-described structure requires wiring patterns for electrically connecting the components related to the light emission of the light-emitting elements, for example, wiring patterns for electrically connecting the drive transistors and the initializing transistors (hereinafter such wiring patterns are referred to as “connecting portions”), and wiring patterns for electrically connecting the drive transistors and the light-emitting elements (hereinafter such wiring patterns are referred to as “electrical continuity portions”). However, if such wiring patterns are formed in different processing steps, the manufacturing process becomes complicated and the manufacturing cost is increased.

0008One solution to solving this problem is to form the connecting portions and the electrical continuity portions simultaneously with the formation of other components (for example, power supply lines) in the same processing step by the patterning of one conductive film. In this method, however, it is necessary to form other components, such as power supply lines, so that they can physically avoid the connecting portions and the electrical continuity portions. Because of such a restriction, for example, a sufficient width of the power supply lines cannot be ensured, and as a result, the resistance of the power supply lines cannot be sufficiently reduced.

SUMMARY

0009An advantage of the invention is that it provides a light-emitting device and an electronic apparatus in which connecting portions and electrical continuity portions are formed from the same layer as that of power supply lines while suppressing the resistance of the power supply lines.

0010According to an aspect of the invention, there is provided a light-emitting device including a drive transistor that controls a current to be supplied to a light-emitting element from a power supply line, an electrical continuity portion that electrically connects the drive transistor with the light-emitting element, an initializing transistor that is turned ON to diode-connect the drive transistor, and a connecting portion that electrically connects the drive transistor with the initializing transistor. The power supply line includes a first portion extending in a predetermined direction, and the electrical continuity portion and the connecting portion are formed from the same layer as that of the power supply line and are located on one side along the width of the first portion across the drive transistor. A specific example of this aspect is discussed below as a first embodiment.

0011According to this configuration, the electrical continuity portion and the connecting portion are formed from the same layer as that of the power supply line. Thus, the manufacturing process can be simplified and the manufacturing cost can be reduced compared with the configuration in which the electrical continuity portion and the connecting portion are formed from a layer different from that of the power supply line. Additionally, since the electrical continuity portion and the connecting portion are disposed on one side along the width of the first portion across the drive transistor, the space for the power supply line can be ensured on the other side along the width of the first portion across the drive transistor. Thus, a sufficient area (or line width) of the power supply line can be formed so that the resistance of the power supply line can be reduced.

0012Forming a plurality of components “from the same layer” is to form the plurality of components in the same step by selectively removing a common film member (it does not matter whether the common film member is a single layer or a plurality of layers), and it does not matter whether the components are connected to each other or are separated from each other.

0013It is preferable that the light-emitting device may further include a capacitor element electrically connected to the gate electrode of the drive transistor. In this case, the capacitor element may be disposed opposite the connecting portion and the electrical continuity portion across the drive transistor, and the first portion of the power supply line may be overlapped with the capacitor element. With this arrangement, since the power supply line can be formed such that it is overlapped with the capacitor element, a more sufficient area can be ensured for the power supply line.

0014It is preferable that the light-emitting device may further include a selection transistor that is turned ON or OFF according to a selection signal. In this case, the gate electrode of the drive transistor may be set to be a potential corresponding to a data signal supplied from a data line via the selection transistor that is turned ON, and the selection transistor may be disposed opposite the drive transistor across the capacitor element. With this arrangement, a sufficient area (line width) of the power supply line can be ensured, and the configuration of the power supply line can be simplified (for example, without notches) compared with the configuration in which the selection transistor is disposed in the gap between the drive transistor and the capacitor element.

0015It is preferable that a plurality of unit elements, each including the drive transistor, the selection transistor, and the initializing transistor, may be disposed in a direction intersecting with the predetermined direction. In this case, the selection transistor may be disposed on one side of the predetermined direction, and the initializing transistor may be disposed on the other side of the predetermined direction. With this arrangement, the selection transistor and the initializing transistor are displaced from each other in the predetermined direction, and accordingly, the gaps among the unit elements can be decreased while maintaining electrical insulation between the selection transistor and the initializing transistor.

0016According to another aspect of the invention, there is provided a light-emitting device including a drive transistor that controls a current to be supplied to a light-emitting element from a power supply line, an electrical continuity portion that electrically connects the drive transistor with the light-emitting element, an initializing transistor that is turned ON to diode-connect the drive transistor, and a connecting portion that electrically connects the drive transistor with the initializing transistor. The power supply line includes a first portion extending in a predetermined direction. The electrical continuity portion and the connecting portion are formed from the same layer as that of the power supply line. The electrical continuity portion is located on one side along the width of the first portion across the drive transistor, and the connecting portion is located on the other side along the width of the first portion across the drive transistor. A specific example of this aspect is discussed below as a second embodiment.

0017According to this configuration, the electrical continuity portion and the connecting portion are formed from the same layer as that of the power supply line. Thus, the manufacturing process can be simplified and the manufacturing cost can be reduced compared with the configuration in which the electrical continuity portion and the connecting portion are formed from a layer different from that of the power supply line. Additionally, since the electrical continuity portion and the connecting portion are respectively located on the two sides across the drive transistor, the space for the power supply line can be ensured in the gap between the electrical continuity portion and the connecting portion. Thus, a sufficient area (or line width) of the power supply line can be formed so that the resistance of the power supply line can be reduced.

0018It is preferable that the light-emitting device may further include a capacitor element electrically connected to a gate electrode of the drive transistor. In this case, the capacitor element may be disposed in a gap between the drive transistor and the connecting portion, and the first portion of the power supply line may be overlapped with the capacitor element. With this arrangement, since the power supply line can be formed such that it is overlapped with the capacitor element, a more sufficient area can be ensured for the power supply line.

0019It is also preferable that the light-emitting device may further include a selection transistor that is turned ON or OFF according to a selection signal. In this case, the gate electrode of the drive transistor may be set to be a potential corresponding to a data signal supplied from a data line via the selection transistor that is turned ON, and the selection transistor may be disposed opposite the drive transistor across the capacitor element. With this arrangement, a sufficient area (line width) of the power supply line can be ensured, and the configuration of the power supply line can be simplified (for example, without notches) compared with the configuration in which the selection transistor is disposed in the gap between the drive transistor and the capacitor element.

0020In the configuration in which the capacitor element is connected to the gate electrode of the drive transistor, the power supply line may be overlapped with part of or the entire capacitor element. Typically, the capacitor element is used for setting or holding the potential of the gate electrode of the drive transistor. For example, the capacitor may be interposed between the gate electrode of the drive transistor and the data line. With this configuration, due to the capacitive coupling in the capacitor element, the gate electrode is set to be the potential corresponding to a change in the potential of the data line. Alternatively, the capacitor element may be interposed between the gate electrode of the drive transistor and the wiring pattern to which a constant potential is supplied. With this configuration, the potential supplied to the gate electrode of the drive transistor from the data line can be held in the capacitor element.

0021It is preferable that a plurality of unit elements, each unit element including the drive transistor, the electrical continuity portion, the initializing transistor, and the connecting portion, may be disposed in a direction intersecting with the predetermined direction. In this case, the power supply line may include a plurality of the first portions corresponding to the unit elements and second portions that interconnect the first portions located adjacent to each other. With this arrangement, the resistance of the power supply line can further be reduced compared with the configuration in which the power supply line includes only the first portion.

0022The above-described light-emitting devices can be used for various types of electronic apparatuses. A typical example of electronic apparatuses is an apparatus utilizing the light-emitting device as a display unit. This type of electronic apparatus includes a personal computer or a cellular telephone. The purpose of the light-emitting device is not restricted to the display of images. The light-emitting device can be used for various other purposes, for example, the light-emitting device can be used for an exposure device (exposure head) for forming latent images on an image carrier, such as a photosensitive drum, by the irradiation of light, a device disposed on the back side of a liquid crystal device to illuminate the liquid crystal device (backlight), or an illumination device that is mounted on an image reader, such as a scanner, to illuminate original documents.

BRIEF DESCRIPTION OF THE DRAWINGS

0023The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

0024<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram illustrating a plurality of unit elements disposed in a light-emitting device.

0025<figref idref="DRAWINGS">FIG. 2</figref> is a circuit diagram illustrating the electrical configuration of each unit element.

0026<figref idref="DRAWINGS">FIG. 3</figref> is a plan view illustrating a unit element according to a first embodiment of the invention.

0027<figref idref="DRAWINGS">FIG. 4</figref> is a sectional view taken long line IV-IV of <figref idref="DRAWINGS">FIG. 3</figref>.

0028<figref idref="DRAWINGS">FIG. 5</figref> is a plan view illustrating a processing step in which a gate insulating layer is formed.

0029<figref idref="DRAWINGS">FIG. 6</figref> is a plan view illustrating a processing step in which a first insulating layer is formed.

0030<figref idref="DRAWINGS">FIG. 7</figref> is a plan view illustrating a processing step in which a second insulating layer is formed.

0031<figref idref="DRAWINGS">FIG. 8</figref> is a plan view illustrating a plurality of unit elements in the processing step in which the first insulating layer is formed.

0032<figref idref="DRAWINGS">FIG. 9</figref> is a plan view illustrating a plurality of unit elements in the processing step in which the second insulating layer is formed.

0033<figref idref="DRAWINGS">FIG. 10</figref> is a sectional view illustrating advantages of the first embodiment.

0034<figref idref="DRAWINGS">FIG. 11</figref> is a circuit diagram illustrating advantages of the first embodiment.

0035<figref idref="DRAWINGS">FIG. 12</figref> is a plan view illustrating a unit element according to a second embodiment of the invention.

0036<figref idref="DRAWINGS">FIG. 13</figref> is a plan view illustrating a processing step in which a gate insulating layer is formed.

0037<figref idref="DRAWINGS">FIG. 14</figref> is a plan view illustrating a processing step in which a first insulating layer is formed.

0038<figref idref="DRAWINGS">FIG. 15</figref> is a plan view illustrating a processing step in which a second insulating layer is foamed.

0039<figref idref="DRAWINGS">FIG. 16</figref> is a plan view illustrating a plurality of unit elements in the processing step in which the second insulating layer is formed.

0040<figref idref="DRAWINGS">FIG. 17</figref> is a plan view illustrating a processing step in which a first insulating layer is formed in a modified example of the second embodiment.

0041<figref idref="DRAWINGS">FIG. 18</figref> is a plan view illustrating a processing step in which a second insulating layer is formed in a modified example of the second embodiment.

0042<figref idref="DRAWINGS">FIG. 19</figref> is a circuit diagram illustrating the configuration of a unit element of a modified example.

0043<figref idref="DRAWINGS">FIG. 20</figref> is a circuit diagram illustrating the configuration of a unit element of another modified example.

0044<figref idref="DRAWINGS">FIG. 21</figref> is a circuit diagram illustrating the configuration of a unit element of another modified example.

0045<figref idref="DRAWINGS">FIG. 22</figref> is a perspective view illustrating a personal computer, which is a specific example of an electronic apparatus according to an embodiment of the invention.

0046<figref idref="DRAWINGS">FIG. 23</figref> is a perspective view illustrating a cellular telephone, which is another specific example of an electronic apparatus according to an embodiment of the invention.

0047<figref idref="DRAWINGS">FIG. 24</figref> is a perspective view illustrating a portable information terminal, which is another specific example of an electronic apparatus according to an embodiment of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

0048Preferred embodiments of the invention are described below with reference to the accompanying drawings.

0000Electrical Configuration of Light-emitting Device

0049<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram illustrating the electrical configuration of a light-emitting device D according to preferred embodiments of the invention. The light-emitting device D includes, as shown in <figref idref="DRAWINGS">FIG. 1</figref>, a plurality of selection lines <b>11</b>, a plurality of initializing lines <b>12</b>, and a plurality of data lines <b>13</b>. The selection lines <b>11</b> and the initializing lines <b>12</b> are extended in the x direction. The data lines <b>13</b> are extended in the Y direction orthogonal to the x direction. A unit element (pixel) P is disposed at the intersection of each pair of the selection lines <b>11</b> and initializing lines <b>12</b> and each data line <b>13</b>. Accordingly, the unit elements P are disposed in a matrix in the x direction and in the Y direction. One unit element P is the minimum unit of light emission. A high power supply potential Vdd is supplied to the unit elements P via power supply lines <b>15</b>.

0050<figref idref="DRAWINGS">FIG. 2</figref> is a circuit diagram illustrating the configuration of each unit element P. A light-emitting element E and a drive transistor Tdr are disposed, as shown in <figref idref="DRAWINGS">FIG. 2</figref>, on the path from the power supply line <b>15</b> to a ground line (ground potential Gnd). The light-emitting element E is an element in which a light-emitting layer <b>23</b> composed of an organic EL material is disposed between a first electrode (positive electrode) <b>21</b> and a second electrode (negative electrode) <b>22</b>. The first electrodes <b>21</b> are formed such that the first electrode <b>21</b> of one unit element P is separated from the first electrode <b>21</b> of the adjacent unit element P. The second electrodes <b>22</b> of the plurality of unit elements P are formed continuously and are grounded. The light-emitting layer <b>23</b> emits light with a light quantity in accordance with the current flowing from the first electrode <b>21</b> to the second electrode <b>22</b>.

0051The drive transistor Tdr is a p-channel thin-film transistor that serves to control the current to be supplied to the light-emitting element E in accordance with the potential Vg of the gate electrode (hereinafter simply referred to as the “gate potential”). The source electrode (S) of the drive transistor Tdr is connected to the power supply line <b>15</b>, while the drain electrode (D) thereof is connected to the first electrode <b>21</b> of the light-emitting element E.

0052An n-channel transistor (hereinafter referred to as the “initializing transistor”) Tint that controls electrical connection between the gate electrode and the drain electrode (first electrode <b>21</b> of the light-emitting element E) of the drive transistor Tdr is disposed between the gate electrode and the drain electrode of the drive transistor Tdr. The gate electrode of the initializing transistor Tint is connected to the initializing line <b>12</b>. An initializing signal Sb is supplied to the initializing line <b>12</b> from a drive circuit (not shown). When the initializing signal Sb reaches an active level to allow the initializing transistor Tint to be turned ON, the gate electrode and the drain electrode of the drive transistor Tdr are electrically connected (diode-connected) to each other.

0053The unit element P includes, as shown in <figref idref="DRAWINGS">FIG. 2</figref>, a capacitor element C<b>1</b> formed of an electrode E<b>1</b> and an electrode E<b>2</b>. The electrode E<b>1</b> is connected to the gate electrode of the drive transistor Tdr. An n-channel transistor (hereinafter referred to as the “selection transistor”) Tsl for controlling electrical connection between the electrode E<b>2</b> and the data line <b>13</b> is disposed therebetween. The gate electrode of the selection transistor Tsl is connected to the selection line <b>11</b>. A selection signal Sa is supplied to the selection line <b>11</b> from a drive circuit (not shown). The conductivity types of the drive transistor Tdr, the selection transistor Tsl, and the initializing transistor Tint can be changed from those shown in <figref idref="DRAWINGS">FIG. 2</figref> if necessary.

0054The operation of one unit element P is described below by individually considering the operation in each of the initializing period, the writing period, and the driving period. In the initializing period, a predetermined potential Vref is supplied to the data line <b>13</b> from a drive circuit (not shown), and also, the selection signal Sa of the selection line <b>11</b> and the initializing signal Sb of the initializing line <b>12</b> are maintained at the active level (high level). Accordingly, the potential Vref is supplied to the electrode E<b>2</b> of the capacitor element C<b>1</b> from the data line <b>13</b> via the selection transistor Tsl. Then, the initializing transistor Tint is turned ON to allow the drive transistor Tdr to be diode-connected. Accordingly, the gate potential Vg of the drive transistor Tdr converges into the difference (Vg=Vdd−Vth) between the power supply potential Vdd supplied to the power supply line <b>15</b> and the threshold voltage Vth of the drive transistor Tdr.

0055Then, in the writing period after the lapse of the initializing period, the initializing signal Sb is shifted to the non-active level (low level). Accordingly, the initializing transistor Tint is turned OFF to allow the diode-connection of the drive transistor Tdr to be canceled. The potential Vref supplied to the electrode E<b>2</b> from the data line <b>13</b> is changed to the potential Vdata while the selection transistor Tsl remains ON. The potential Vdata is a potential corresponding to the grayscale level specified by the unit element P.

0056The impedance of the gate electrode of the drive transistor Tdr is sufficiently high. Accordingly, if the potential of the electrode E<b>2</b> is changed from the potential Vref to the data potential Vdata by ΔV (=Vref−Vdata), the potential of the electrode E<b>1</b> is also changed from the potential Vg(=Vdd−Vth) set in the initializing period due to capacitive coupling in the capacitor element C<b>1</b>. In this case, a change in the potential of the electrode E<b>1</b> is determined by the ratio of the capacitance of the capacitor element C<b>1</b> to other parasitic capacitances, for example, the gate capacitance of the drive transistor Tdr and parasitic capacitances of other wiring patterns. More specifically, when the capacitance of the capacitor element C<b>1</b> is represented by C and when the parasitic capacitances are indicated by Cs, a change in the potential of the electrode E<b>1</b> can be indicated by ΔV·C/(C+Cs). Accordingly, the gate potential Vg of the drive transistor Tdr is changed to the level expressed by equation (1) at the end of the writing period: <br /><i>Vg=Vdd−Vth−k·ΔV</i>  (1)<br /> where k=C/(C+Cs).

0057In the driving period after the lapse of the writing period, the selection signal Sa is shifted to the non-active level to allow the selection transistor Tsl to be turned OFF. Then, the current corresponding to the gate potential Vg of the drive transistor Tdr is supplied to the light-emitting element E from the power supply line <b>15</b> through the source electrode and the drain electrode of the drive transistor Tdr. The light-emitting element E then emits light with the light quantity corresponding to the data potential Vdata,

0058The current I supplied to the light-emitting element E in the driving period can be expressed by equation (2), assuming that the drive transistor Tdr is operated in a saturation region:

0059<maths id="MATH-US-00001" num="00001"><math overflow="scroll"><mtable><mtr><mtd><mtable><mtr><mtd><mrow><mi>I</mi><mo>=</mo><mrow><mrow><mo>(</mo><mrow><mi>β</mi><mo>/</mo><mn>2</mn></mrow><mo>)</mo></mrow><mo>⁢</mo><mrow><mo>(</mo><mrow><mi>Vgs</mi><mo>-</mo><mi>Vth</mi></mrow><mo>)</mo></mrow><mo>⁢</mo><mn>2</mn></mrow></mrow></mtd></mtr><mtr><mtd><mrow><mo>=</mo><mrow><mrow><mo>(</mo><mrow><mi>β</mi><mo>/</mo><mn>2</mn></mrow><mo>)</mo></mrow><mo>⁢</mo><mrow><mo>(</mo><mrow><mi>Vdd</mi><mo>-</mo><mi>Vg</mi><mo>-</mo><mi>Vth</mi></mrow><mo>)</mo></mrow><mo>⁢</mo><mn>2</mn></mrow></mrow></mtd></mtr></mtable></mtd><mtd><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="US8772789B2_D0001.tif" /><br /> where β designates the gain coefficient of the drive transistor Tdr, and Vgs indicates the gate-source voltage of the drive transistor Tdr.

0060Equation (2) can be modified as follows by substituting equation (1) into equation (2). <br /><i>I</i>=(β/2)(<i>k·ΔV</i>)2

0061That is, the current I supplied to the light-emitting element E is not influenced by the threshold voltage Vth of the drive transistor Tdr. It is thus possible to suppress errors of the light quantities (non-uniformities of the luminance) of the light-emitting elements E caused by variations of the threshold voltages Vth of the drive transistors Tdr. Such variations are originated from the deviations of the threshold voltage Vth from the design value or the difference in the drive transistors Tdr of the unit elements P.

0000Specific Structure of Unit Element P

0062The specific structure of the above-described unit elements P is described below with reference to the accompanying drawings. For the sake of convenience of description, the dimensions and ratios of the components shown in the drawings are changed from those of the actual devices if necessary.

First Embodiment

0063A description is given below of the specific structure of the unit elements P of the light-emitting device D according to a first embodiment of the invention. <figref idref="DRAWINGS">FIG. 3</figref> is a plan view illustrating one unit element P, and <figref idref="DRAWINGS">FIG. 4</figref> is a sectional view taken along line IV-IV of <figref idref="DRAWINGS">FIG. 3</figref>. Although <figref idref="DRAWINGS">FIG. 3</figref> is a plan view, for easy understanding, the components shown in <figref idref="DRAWINGS">FIG. 3</figref> corresponding to the counterparts in <figref idref="DRAWINGS">FIG. 4</figref> are hatched in a manner similar to the counterparts in <figref idref="DRAWINGS">FIG. 4</figref>. The same applies to the other plan views.

0064The components, such as the drive transistor Tdr and the light-emitting element E, of the unit element P shown in <figref idref="DRAWINGS">FIG. 2</figref> are formed, as shown in <figref idref="DRAWINGS">FIG. 4</figref>, on the surface of a substrate <b>10</b>. The substrate <b>10</b> is a planar member composed of an insulating material, such as glass or plastic. When forming the components of the unit element P on the surface of the substrate <b>10</b>, an insulating film, such as a silicon oxide or silicon nitride film, covering the substrate <b>10</b> may be used as an underlayer of the components. Since the light-emitting device D of the first embodiment is a top emission type, it is not always necessary that the substrate <b>10</b> exhibit a light transmittance characteristic.

0065<figref idref="DRAWINGS">FIGS. 5 through 7</figref> are plan views illustrating the surface of the substrate <b>10</b> when the unit element P is formed on the substrate <b>10</b> in various processing steps. In <figref idref="DRAWINGS">FIGS. 5 through 7</figref>, a region A in which the first electrode <b>21</b> shown in <figref idref="DRAWINGS">FIG. 3</figref> is to be formed is indicated by the two-dot-chain lines.

0066A semiconductor layer <b>31</b> and a semiconductor layer <b>41</b> are formed, as shown in <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, on the surface of the substrate <b>10</b> by a semiconductor material, such as silicon. The semiconductor layer <b>31</b> and the semiconductor layer <b>41</b> are simultaneously formed in the same step by the patterning of a film member that is continuously formed on the entire area of the substrate <b>10</b>. As in the relationship between the semiconductor layer <b>31</b> and the semiconductor layer <b>41</b>, forming a plurality of components in the same step by selectively removing a common film member (it does not matter whether the common film member is a single layer or a plurality of layers) is referred to as “forming components from the same layer”. The components formed from the same layer are composed of the same material, and have substantially the same thickness. With this configuration, the manufacturing process can be simplified and the manufacturing cost can be reduced, compared with the case where components are formed from different layers.

0067The semiconductor layer <b>31</b> includes, as shown in <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, a first element portion <b>311</b> and a second element portion <b>312</b>. The first element portion <b>311</b>, which is formed substantially in a rectangular shape, serves as the semiconductor layer of the drive transistor Tdr. The second element portion <b>312</b> serves as the semiconductor layer of the initializing transistor Tint. The second element portion <b>312</b> is formed toward the positive side in the x direction and toward the negative side in the Y direction (i.e., at the top right of the first element portion <b>311</b>) when viewed from the first element portion <b>311</b>. More specifically, as shown in <figref idref="DRAWINGS">FIG. 5</figref>, the second element portion <b>312</b> includes a part <b>312</b><i>a </i>extending toward the negative side in the Y direction from the first element portion <b>311</b>, a part <b>312</b><i>b </i>extending toward the positive side in the x direction from the part <b>312</b><i>a</i>, and a part <b>312</b><i>c </i>extending toward the positive side in the Y direction from the part <b>312</b><i>b. </i>

0068The semiconductor layer <b>41</b>, which is disposed toward the positive side in the Y direction when viewed from the semiconductor layer <b>31</b>, includes the electrode E<b>2</b>, which is formed substantially in a rectangular shape and forms the capacitor element C<b>1</b> shown in <figref idref="DRAWINGS">FIG. 2</figref>, and an element portion <b>411</b> extending in the Y direction from the electrode E<b>2</b>. The element portion <b>411</b> serves as the semiconductor layer of the selection transistor Tsl, and is formed toward the negative side in the x direction and toward the positive side in the Y direction (i.e., at the bottom left of the electrode E<b>2</b>) when viewed from the electrode E<b>2</b>.

0069As shown in <figref idref="DRAWINGS">FIG. 4</figref>, the entire surface of the substrate <b>10</b> on which the semiconductor layer <b>31</b> and the semiconductor layer <b>41</b> are formed is covered with a gate insulating layer L<b>0</b>. On the surface of the gate insulating layer L<b>0</b>, as shown in <figref idref="DRAWINGS">FIGS. 4 and 6</figref>, the selection line <b>11</b>, the initializing line <b>12</b>, an intermediate conductor <b>51</b>, and a first data line portion <b>131</b> are formed from the same layer.

0070The selection line <b>11</b> is extended in the x direction over the plurality of unit elements P and is overlapped with the element portion <b>411</b> of the semiconductor layer <b>41</b>. The area of the element portion <b>411</b> that is overlapped with the selection line <b>11</b> across the gate insulating layer L<b>0</b> serves as the channel region of the selection transistor Tsl. The initializing line <b>12</b> is extended in the x direction over the plurality of unit elements P and is overlapped with the second element portion <b>312</b> of the semiconductor layer <b>31</b>. The area of the part <b>312</b><i>a </i>or the area of the part <b>312</b><i>c </i>that is overlapped with the initializing line <b>12</b> across the gate insulating layer L<b>0</b> serves as the channel region of the initializing transistor Tint. Accordingly, the initializing transistor Tint in this embodiment is a dual-gate-structured transistor.

0071The intermediate conductor <b>51</b> is formed in the gap between the selection line <b>11</b> and the initializing line <b>12</b>, and includes the electrode E<b>1</b>, a gate electrode <b>511</b>, and an interconnecting portion <b>513</b>. The electrode E<b>1</b> is formed substantially in a rectangular shape and is overlapped with the electrode E<b>2</b> of the semiconductor layer <b>41</b> when viewed perpendicularly to the substrate <b>10</b>. The electrode E<b>1</b> and the electrode E<b>2</b> face each other across the gate insulating layer L<b>0</b> (dielectric), as shown in <figref idref="DRAWINGS">FIGS. 4 and 6</figref> so that they form the capacitor element C<b>1</b> shown in <figref idref="DRAWINGS">FIG. 2</figref>.

0072The interconnecting portion <b>513</b> is extended toward the negative side in the Y direction from the top right of the electrode E<b>1</b>. The gate electrode <b>511</b> is extended toward the negative side in the x direction from the interconnecting portion <b>513</b> such that it faces the electrode E<b>1</b> with a gap therebetween, and is overlapped with the first element portion <b>311</b> over the entire width (X direction) thereof. As shown in <figref idref="DRAWINGS">FIG. 4</figref>, the area of the first element portion <b>311</b> that faces the gate electrode <b>511</b> across the insulating layer L<b>0</b> serves as a channel region <b>311</b><i>c </i>of the drive transistor Tdr. The area of the first element portion <b>311</b> that is located closer to the electrode E<b>2</b> than the channel region <b>311</b><i>c </i>(i.e., the area located in the gap between the gate electrode <b>511</b> and the electrode E<b>1</b>, as shown in <figref idref="DRAWINGS">FIG. 6</figref>, when viewed perpendicularly to the substrate <b>10</b>) is a source region <b>311</b><i>s</i>, and the area of the first element portion <b>311</b> that is located opposite the source region <b>311</b><i>s </i>is a drain region <b>311</b><i>d. </i>

0073The first data line portion <b>131</b> forms the data line <b>13</b> shown in <figref idref="DRAWINGS">FIG. 2</figref>. The first data line portion <b>131</b> is disposed toward the negative side in the x direction when viewed from the intermediate conductor <b>51</b> and is extended in the Y direction in the gap between the selection line <b>11</b> and the initializing line <b>12</b>.

0074<figref idref="DRAWINGS">FIG. 8</figref> is a plan view illustrating four unit elements P that are in the processing step shown in <figref idref="DRAWINGS">FIG. 6</figref> and are disposed in the x direction and in the Y direction. In each unit element P, as shown in <figref idref="DRAWINGS">FIGS. 6 and 8</figref>, the second element portion <b>312</b> (initializing transistor Tint) formed at the periphery of the negative side in the Y direction is located toward the positive side in the x direction, while the element portion <b>411</b> (selection transistor Tsl) formed at the periphery of the negative side in the Y direction is located toward the negative side in the x direction.

0075It is now assumed that the second element portion <b>312</b> and the element portion <b>411</b> are disposed toward the same side in the x direction in each unit element P. With this configuration, it is necessary to ensure a sufficient gap (indicated by region B in <figref idref="DRAWINGS">FIG. 8</figref>) between unit elements P adjacent to each other in the Y direction so that the second element portion <b>312</b> and the element portion <b>411</b> can be separated from each other. With this configuration, the high definition of the unit elements P is impaired. According to this embodiment, however, the second element portion <b>312</b> and the element portion <b>411</b> are displaced from each other in the x direction, and thus, the second element portion <b>312</b> and the element portion <b>411</b> are alternately disposed in the x direction in the region B. With this configuration, even if the width of the region B is decreased, the second element portion <b>312</b> and the element portion <b>411</b> can be separated from each other, and the high definition of the unit elements P can be implemented.

0076The entire surface of the gate insulating layer L<b>0</b> on which the intermediate conductor <b>51</b> and the first data line portion <b>131</b> are formed is, as shown in <figref idref="DRAWINGS">FIG. 4</figref>, covered with a first insulating layer L<b>1</b>. On the surface of the first insulating layer L<b>1</b>, as shown in <figref idref="DRAWINGS">FIGS. 4 and 7</figref>, a connecting portion <b>61</b>, an electrical continuity portion <b>71</b>, the power supply line <b>15</b>, and a second data line portion <b>132</b> are formed from the same layer composed of a conductive material.

0077When viewed perpendicularly to the substrate <b>10</b>, as shown in <figref idref="DRAWINGS">FIG. 7</figref>, the connecting portion <b>61</b> is overlapped with the end of the part <b>312</b><i>c </i>of the second element portion <b>312</b> located at the positive side in the Y direction and also overlapped with the intermediate conductor <b>51</b> (gate electrode <b>511</b>). The connecting portion <b>61</b> is electrically connected to the part <b>312</b><i>c </i>through a contact hole Ha<b>1</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b>, and is also electrically connected to the intermediate conductor <b>51</b> through a contact hole Ha<b>2</b> passing the first insulating layer L<b>1</b>. That is, the gate electrode <b>511</b> (electrode E<b>1</b> of the capacitor element C<b>1</b>) of the drive transistor Tdr and the initializing transistor Tint are electrically connected to each other through the connecting portion <b>61</b>. In this specification, contact holes are used for electrically connecting the components disposed on one side of an insulating layer with the components disposed on the other side of the insulating layer, and more specifically, the contact holes are, for example, holes passing through the insulating layer along the thickness thereof. The planar configuration of the contact holes can be determined as desired.

0078The electrical continuity portion <b>71</b> is disposed between the drive transistor Tdr and the light-emitting element E to electrically connect them. When viewed perpendicularly to the substrate <b>10</b>, the electrical continuity portion <b>71</b> is located opposite the capacitor element C<b>1</b> across the drive transistor Tdr (i.e., in the region toward the negative side in the Y direction with respect to the drive transistor Tdr). In this embodiment, the electrical continuity portion <b>71</b> is configured such that, when viewed perpendicularly to the substrate <b>10</b>, a part <b>711</b> that is overlapped with the drain region <b>311</b><i>d </i>of the first element portion <b>311</b> is continuously formed with a part <b>712</b> located opposite the part <b>711</b> across the initializing portion <b>12</b>.

0079In the area of the first insulating layer L<b>1</b> that is overlapped with the drain region <b>311</b><i>d</i>, when viewed perpendicularly to the substrate <b>10</b>, a plurality of contact holes Ha<b>3</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b> are formed. The contact holes Ha<b>3</b> are disposed in the x direction in which the gate electrode <b>511</b> is extended (i.e., in the direction along the channel width of the drive transistor Tdr). The part <b>711</b> of the electrical continuity portion <b>71</b> is electrically connected to the drain region <b>311</b><i>d </i>of the drive transistor Tdr through the contact holes Ha<b>3</b>.

0080<figref idref="DRAWINGS">FIG. 9</figref> is a plan view illustrating the four unit elements P that are in the processing step shown in <figref idref="DRAWINGS">FIG. 8</figref> and are disposed in the x direction and in the Y direction. The power supply lines <b>15</b> are bar-like wiring patterns, as shown in <figref idref="DRAWINGS">FIGS. 7 and 9</figref>, which extend in the x direction in which the plurality of unit elements P are disposed. The power supply line <b>15</b> is overlapped with the capacitor element C<b>1</b> of each unit element P and the source region <b>311</b><i>s </i>of the drive transistor Tdr, when viewed perpendicularly to the substrate <b>10</b>. In the area of the first insulating layer L<b>1</b> that is overlapped with the source region <b>311</b><i>s</i>, a plurality of contact holes Ha<b>4</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b> are formed, as shown in <figref idref="DRAWINGS">FIG. 7</figref>. The contact holes Ha<b>4</b> are located in the x direction in which the gate electrode <b>511</b> is extended. The power supply line <b>15</b> is electrically connected to the source region <b>311</b><i>s </i>of the drive transistor Tdr through the contact holes Ha<b>4</b>.

0081In this embodiment, the configuration and dimensions of the power supply lines <b>15</b> are determined so that the power supply lines <b>15</b> are not overlapped with the selection transistors Tsl (element portions <b>411</b>), the selection lines <b>11</b>, the initializing transistors Tint (second element portion <b>312</b>), and the initializing lines <b>12</b>, when viewed perpendicularly to the substrate <b>10</b>. In other words, the power supply lines <b>15</b> are extended in the x direction, as shown in <figref idref="DRAWINGS">FIG. 9</figref>, in the gap between the selection transistors Tsl disposed along the selection lines <b>11</b> and the initializing transistors Tint disposed along the initializing lines <b>12</b>.

0082The second data line portion <b>132</b> forms, together with the first data line portion <b>131</b>, the data line <b>13</b>, and is extended in the Y direction in the gap between adjacent power supply lines <b>15</b>, as shown in <figref idref="DRAWINGS">FIGS. 7 and 9</figref>. An end <b>132</b><i>a </i>of the second data line portion <b>132</b> located at the positive (lower) side in the Y direction is overlapped with, as shown in <figref idref="DRAWINGS">FIG. 7</figref>, an end <b>131</b><i>a </i>(see <figref idref="DRAWINGS">FIG. 6</figref>) of the first data line portion <b>131</b> located at the negative (upper) side in the Y direction. The end <b>132</b><i>a </i>and the end <b>131</b><i>a </i>are electrically connected to each other through the contact hole Ha<b>5</b> passing through the first insulating layer L<b>1</b>. Similarly, an end <b>132</b><i>b </i>of the second data line portion <b>132</b> located at the negative side in the Y direction is overlapped with, as shown in <figref idref="DRAWINGS">FIG. 7</figref>, an end <b>131</b><i>b </i>(see <figref idref="DRAWINGS">FIG. 6</figref>) of the first data line portion <b>131</b> located at the positive side in the Y direction through a contact hole Ha<b>6</b>. In this manner, the first data line portions <b>131</b> and the second data line portions <b>132</b> which are alternately disposed in the Y direction are electrically connected to each other so that the data lines <b>13</b> linearly extending in the Y direction can be formed.

0083A branched portion <b>134</b> is continuously provided, as shown in <figref idref="DRAWINGS">FIG. 7</figref>, from the second data line portion <b>132</b>. The branched portion <b>134</b> is located opposite the capacitor element C<b>1</b> across the selection line <b>11</b>, and is extended in the x direction to be overlapped with the element portion <b>411</b> of the semiconductor layer <b>41</b>. The branched portion <b>134</b> is electrically connected to the element portion <b>411</b> through a contact hole Ha<b>7</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b>. That is, the selection transistor Tsl and the data line <b>13</b> are electrically connected to each other through the branched portion <b>134</b>.

0084The capacitor element C<b>1</b> of each unit element P is, as shown in <figref idref="DRAWINGS">FIGS. 7 and 9</figref>, located adjacent to the data line <b>13</b> of the right-adjacent unit element P located at the positive side in the x direction. <figref idref="DRAWINGS">FIG. 10</figref> is an enlarged, sectional view illustrating one unit element P<b>1</b> and the right-adjacent unit element P<b>2</b> located at the positive side in the x direction. In <figref idref="DRAWINGS">FIG. 10</figref>, the intermediate conductor <b>51</b> (in particular, the electrode E<b>1</b> of the capacitor element C<b>1</b>) of the unit element P<b>1</b> and the first data line portion <b>131</b> of the data line <b>13</b> corresponding to the unit element P<b>2</b> are shown.

0085The intermediate conductor <b>51</b> and the first data line portion <b>131</b> are formed from the same layer and are thus located adjacent to each other. Accordingly, a capacitor (parasitic capacitor) Ca is formed due to capacitive coupling between the intermediate conductor <b>51</b> and the first data line portion <b>131</b>. Thus, although the potential Vg of the electrode E<b>1</b> (and the gate electrode <b>511</b> of the drive transistor Tdr) of the unit element P<b>1</b> is set intrinsically only by a change in the potential of the data line <b>13</b> corresponding to the unit element P<b>1</b> (i.e., the voltage corresponding to the grayscale level of the unit element P<b>1</b>), it is also influenced by a change in the potential of the first data line portion <b>131</b> corresponding to the unit element P<b>2</b> (i.e., the voltage corresponding to the grayscale level of the unit element P<b>2</b>). That is, it is difficult to precisely set the gate potential Vg of the drive transistor Tdr of each unit element P, and errors may occur in the light quantities of the light-emitting elements E.

0086The first data line portion <b>131</b> and the power supply line <b>15</b> face each other across the first insulating layer L<b>1</b>, as shown in <figref idref="DRAWINGS">FIG. 10</figref>, so that a capacitance is formed therebetween. In this embodiment, as shown in <figref idref="DRAWINGS">FIG. 10</figref>, the capacitance c<b>2</b> of the capacitor Cb formed between the first data line portion <b>131</b> of the unit element P<b>2</b> and the power supply line <b>15</b> is larger than the capacitance c<b>1</b> of the capacitor Ca formed between the first data line portion <b>131</b> and the intermediate conductor <b>51</b> (electrode E<b>1</b>) of the unit element P<b>1</b>. With this configuration, the influence on the intermediate conductor <b>51</b> (electrode E<b>1</b>) of the unit element P<b>1</b> caused by a change in the potential of the first data line portion <b>131</b> of the unit element P<b>2</b> is alleviated by the capacitor Cb. Accordingly, the gate potential Vg of the drive transistor Tdr of each unit element P and the light quantity of the light-emitting element E corresponding to the gate potential Vg can be set to desired values with high precision.

0087In this embodiment, the distance (thickness of the first insulting layer L<b>1</b>) between the first data line portion <b>131</b> and the power supply line <b>15</b> and the space between the intermediate conductor <b>51</b> of the unit element P<b>1</b> and the first data line portion <b>131</b> of the unit element P<b>2</b> are determined so that the above-described condition (c<b>2</b>>c<b>1</b>) is satisfied. More specifically, the distance (thickness of the first insulting layer L<b>1</b>) between the first data line portion <b>131</b> of the unit element P<b>2</b> and the power supply line <b>15</b> is smaller than the space between the intermediate conductor <b>51</b> of the unit element P<b>1</b> and the first data line portion <b>131</b> of the unit element P<b>2</b>. Additionally, the area by which the first data line portion <b>131</b> of the unit element P<b>2</b> faces the power supply line <b>15</b> through the first insulating layer L<b>1</b> (i.e., the area of the first data line portion <b>131</b> that is overlapped with the power supply line <b>15</b> when viewed perpendicularly to the substrate <b>10</b>) is larger than the area by which the first data line portion <b>131</b> faces the intermediate conductor <b>151</b> of the unit element P<b>1</b> (i.e., the area by which the side surface of the intermediate conductor <b>51</b>, when viewed perpendicularly to the substrate <b>10</b>, faces the side surface of the first data line portion <b>131</b>). By selecting the dimensions of the components and spaces between the components as described above, the capacitance c<b>2</b> can be set to be larger than the capacitance c<b>1</b>.

0088To precisely set the gate potential Vg of the drive transistor Tdr in accordance with the data potential Vdata of the data line <b>13</b>, it is desirable that the capacitance c<b>2</b> of the capacitor Cb of the unit element P<b>2</b> is smaller than the capacitance C of the capacitor element C<b>1</b> of the unit element P<b>2</b> (synthesized capacitance of the capacitor element C<b>1</b> and parasitic capacitance Cs if the parasitic capacitor Cs is formed in the gate electrode <b>511</b>). To satisfy this condition, the gap between the first data line portion <b>131</b> and the power supply line <b>15</b> is set to be larger than the gap between the electrode E<b>1</b> and the electrode E<b>2</b> of the capacitor element C<b>1</b>. More specifically, the thickness of the first insulating layer L<b>1</b> intervening between the first data line portion <b>131</b> and the power supply line <b>15</b> (i.e., the thickness of the dielectric member of the capacitor Cb) is set to be larger than the thickness of the gate insulating layer L<b>0</b> intervening between the electrode E<b>1</b> and the electrode E<b>2</b> (i.e., the thickness of the dielectric member of the capacitor element C<b>1</b>). Additionally, the area by which the electrode E<b>1</b> and the electrode E<b>2</b> face each other (i.e., the area of the capacitor element C<b>1</b>) is set to be larger than the area by which the first data line portion <b>131</b> and the power supply line <b>15</b> face each other. With this arrangement, the capacitance c<b>2</b> of the capacitor Cb becomes smaller than the capacitance C of the capacitor element C<b>1</b>.

0089As shown in <figref idref="DRAWINGS">FIG. 4</figref>, the entire surface of the first insulating layer L<b>1</b> on which the second data line portion <b>132</b> and the power supply line <b>15</b> are formed is covered with a second insulating layer L<b>2</b>. The first electrode <b>21</b> is formed, as shown in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, on the surface of the second insulating layer L<b>2</b>. The first electrode <b>21</b> is formed substantially in a rectangular shape and is overlapped with the electrical continuity portion <b>71</b>, the drive transistor Tdr, and the capacitor element C<b>1</b>, when viewed perpendicularly to the substrate <b>10</b>. In this embodiment, the first electrode <b>21</b> is formed of a light-reflective, conductive material, such as a metal, for example, aluminum or silver, or an alloy essentially consisting of such a metal. The first electrode <b>21</b> is electrically connected to the part <b>712</b> of the electrical continuity portion <b>71</b> through a contact hole Ha<b>8</b> passing through the second insulating layer L<b>2</b>. That is, the drain region <b>311</b><i>d </i>of the drive transistor Tdr is electrically connected to the first electrode <b>21</b> of the light-emitting element E through the electrical continuity portion <b>71</b>.

0090Barriers <b>25</b> that partition the boundaries of the unit elements P are formed in a lattice-like shape on the surface of the second insulating layer L<b>2</b> on which the first electrodes <b>21</b> are formed. The barriers <b>25</b> have the function of electrically insulating the first electrodes <b>21</b> located adjacent to each other, i.e., the function of controlling the potentials of the individual first electrodes <b>21</b>. The light-emitting layer <b>23</b> of each light-emitting element E is enclosed in the inner periphery of the barrier <b>25</b> and is formed in a recess having the first electrode <b>21</b> as the bottom surface. Various functional layers (hole injection layer, hole transport layer, electron injection layer, electron transport layer, hole block layer, and electron block layer) for promoting or making efficient the light emission of the light-emitting layer <b>23</b> may be laminated on the light-emitting layer <b>23</b>.

0091The second electrode <b>22</b> are formed continuously over the plurality of unit elements P, and covers the light-emitting layer <b>23</b> and the barrier <b>25</b>. Accordingly, the barrier <b>25</b> serves the function of electrically insulating the first electrode <b>21</b> from the second electrode <b>22</b> in the gap of each light-emitting element E. In other words, the barrier <b>25</b> defines the area in which the current flows between the first electrode <b>21</b> and the second electrode <b>22</b> (i.e., the light-emitting area). The second electrode <b>22</b> is formed of a light-transmissive, conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). Accordingly, light emitted from the light-emitting layer <b>23</b> toward the side opposite the substrate <b>10</b> and light emitted from the light-emitting layer <b>23</b> toward the substrate <b>10</b> and reflected on the surface of the first electrode <b>21</b> pass through the second electrode <b>22</b> and are output. That is, the light-emitting device D of this embodiment is a top emission type.

0092The entire surface of the second electrode <b>22</b> is covered with a sealing material (not shown). The sealing material includes a first layer that protects the second electrode <b>22</b>, a second layer that flattens the difference in the level of the surface of the second electrode <b>22</b>, a third layer (barrier layer) that prevents the entry of impurities (for example, water) into the second electrode <b>22</b> and the light-emitting layer <b>23</b>, the first layer, the second layer, and the third layer being laminated from the second electrode <b>22</b> in that order.

0093As described above, in this embodiment, the electrical continuity portion <b>71</b> is located opposite the capacitor element C<b>1</b> across the drive transistor Tdr. With this configuration, the effect of reducing the capacitance required for the capacitor element C<b>1</b> can be achieved. This effect is described below more specifically.

0094It is now assumed that the electrical continuity portion <b>71</b> is disposed in the gap between the drive transistor Tdr and the capacitor element C<b>1</b> when viewed perpendicularly to the substrate <b>10</b> (such a configuration is referred to as “configuration 1”). In the configuration 1, the electrode E<b>1</b> of the capacitor element C<b>1</b> and the electrical continuity portion <b>71</b> are located in proximity with each other across the first insulating layer L<b>1</b>. Accordingly, a capacitance Cx is formed between the electrode E<b>1</b> and the electrical continuity portion <b>71</b> (first electrode <b>21</b>), as indicated by the broken lines in <figref idref="DRAWINGS">FIG. 11</figref>.

0095During the writing period, the potential of the electrode E<b>1</b> is changed by ΔV·C/(C+Cs). In the configuration 1, the capacitance Cs is increased by the capacitance Cx compared with the case where the electrode E<b>1</b> and the electrical continuity portion <b>71</b> are not capacitively coupled to each other. Accordingly, the fluctuations of the gate potential Vg of the drive transistor Tdr in response to the change ΔV in the potential of the data line <b>13</b> are restricted. Thus, in order to fluctuate the gate potential Vg in a wide range in response to the change ΔV in the potential of the data line <b>13</b> (i.e., to ensure a sufficient range of the light quantities of the light-emitting element E), it is necessary to ensure a sufficient capacitance C of the capacitor element C<b>1</b> by reducing the thickness of the gate insulating layer L<b>0</b> or increasing the areas of the electrode E<b>1</b> and the electrode E<b>2</b>. Since there are limitations on reducing the thickness of the gate insulating layer L<b>0</b>, it is necessary to increase the areas of the electrode E<b>1</b> and the electrode E<b>2</b>. On the other hand, however, an increase in the area of the capacitor element C<b>1</b> impairs the high definition of the unit elements P.

0096If the electrode E<b>1</b> and the electrical continuity portion <b>71</b> are separated from each other by forming the first insulating layer L<b>1</b> to be sufficiently thick, the capacitance Cx can be reduced in the configuration 1. However, if the first insulating layer L<b>1</b> is formed to be thick, defects related to film formation, such as cracks, are likely to occur, and also, the perfect electrical continuity among the components cannot be established due to the defects of contact holes (for example, contact holes cannot be perfectly formed from the first insulating layer L<b>1</b>). Thus, there are also limitations on reducing the capacitance Cx by this method.

0097In contrast, according to this embodiment, since the electrical continuity portion <b>71</b> is disposed opposite the capacitor element C<b>1</b> across the drive transistor Tdr, the capacitance Cx generated between the electrode E<b>1</b> and the electrical continuity portion <b>71</b> can be reduced to a sufficient level compared with the configuration 1. Accordingly, the gate potential Vg of the gate electrode <b>511</b> of the drive transistor Tdr (and the light quantity of the light-emitting element E) can be changed in a wide range without the need to considerably increase the area of the capacitor element E<b>1</b> as in the configuration 1.

0098In this embodiment, both the electrical continuity portion <b>71</b> and the connecting portion <b>61</b> formed from the same layer as that of the power supply line <b>15</b> are located farther toward the negative side in the Y direction than the drive transistor Tdr (i.e., on one side along the width of the power supply line <b>15</b>) when viewed perpendicularly to the substrate <b>10</b>. With this configuration, a sufficient space can be ensured for the power supply line <b>15</b> on the surface of the first insulating layer L<b>1</b> farther toward the positive side in the Y direction than drive transistor Tdr (i.e., on the other side along the width of the power supply line <b>15</b>). Accordingly, the power supply line <b>15</b> can be formed to be wide so that the resistance can be sufficiently reduced. In particular, in this embodiment, since the power supply line <b>15</b> can be formed such that it is overlapped with the capacitor element C<b>1</b>, the resistance of the power supply line <b>15</b> can be reduced more considerably compared with the configuration in which the power supply line <b>15</b> is overlapped with only the source region <b>31</b><i>s </i>of the drive transistor Tdr. The reduced resistance of the power supply line <b>15</b> suppresses a voltage drop in the power supply line <b>15</b>. As a result, variations in the power supply potential Vdd supplied to the unit elements P and variations in the light quantities of the light-emitting elements E can be reduced.

0099In the configuration in which the electrical continuity portion <b>71</b> and the connecting portion <b>61</b> are disposed in the gap between the drive transistor Tdr and the capacitor element C<b>1</b>, it is necessary to form the power supply line <b>15</b> such that it can physically avoid the electrical continuity portion <b>71</b> and the connecting portion <b>61</b>. However, the complexity of the configuration of the power supply line <b>15</b> encourages a break or damage in the power supply line <b>15</b> because of the manufacturing technique. Conversely, according to this embodiment, since a space can be ensured for the power supply line <b>15</b> opposite the electrical continuity portion <b>71</b> and the connecting portion <b>61</b> across the drive transistor Tdr, the power supply line <b>15</b> can be formed in a simple bar-like shape, as shown in <figref idref="DRAWINGS">FIG. 7</figref>. As a result, a break or damage in the power supply line <b>15</b> can be suppressed so that the yield of the light-emitting devices D can be improved.

0100With a view to reducing the resistance of the power supply line <b>15</b>, the power supply line <b>15</b> could be overlapped with, not only the drive transistor Tdr and the capacitor element C<b>1</b>, but also the selection transistor Tsl and the initializing transistor Tint. Such a configuration is hereinafter referred to as “configuration 2”. In the configuration 2, however, the selection transistor Tsl or the selection line <b>11</b> is capacitively coupled to the power supply line <b>15</b> (i.e., a parasitic capacitance is generated therebetween), which encourages the occurrence of blunt waves in the selection signal Sa. Similarly, the capacitance generated between the initializing transistor Tint or the initializing line <b>12</b> and the power supply line <b>15</b> may cause blunt waves in the initializing signal Sb. Thus, in the configuration 2, the switching of the selection transistor Tsl or the initializing transistor Tint may be delayed.

0101On the other hand, according to this embodiment, when viewed perpendicularly to the substrate <b>10</b>, the power supply line <b>15</b> is not overlapped with the selection transistor Tsl or the selection line <b>11</b> or the initializing transistor Tint or the initializing line <b>12</b>. Accordingly, the capacitance between the power supply line <b>15</b> and the selection transistor Tsl or the selection line <b>11</b> or the initializing transistor Tint or the initializing line is smaller than that of the configuration 2. Thus, the occurrence of blunt waves in the selection signal Sa or the initializing signal Sb can be suppressed so that the fast operation of the selection transistor Tsl or the initializing transistor Tint can be achieved.

Second Embodiment

0102The specific configuration of a unit element P according to a second embodiment of the invention is described below. <figref idref="DRAWINGS">FIG. 12</figref> is a plan view illustrating the configuration of the unit element P of the second embodiment. <figref idref="DRAWINGS">FIGS. 13 through 15</figref> are plan views illustrating the surface of the substrate <b>10</b> when the unit element P is formed on the substrate <b>10</b> in various processing steps. In the following description, the same components as those of the first embodiment are designated with like reference numerals, and an explanation thereof is thus omitted.

0103On the surface of the substrate <b>10</b>, as shown in <figref idref="DRAWINGS">FIG. 13</figref>, a semiconductor layer <b>32</b>, a semiconductor layer <b>42</b>, and a semiconductor layer <b>45</b> are formed from the same layer by using a semiconductor material. The semiconductor layer <b>32</b>, which is formed substantially in a rectangular shape, forms the drive transistor Tdr. The semiconductor layer <b>42</b> is formed toward the positive side in the Y direction when viewed from the semiconductor layer <b>32</b>, and includes a substantially rectangular electrode E<b>2</b> and an element portion <b>421</b> extending in the x direction from the bottom left portion of the electrode E<b>2</b>. The element portion <b>421</b> functions as the semiconductor layer of the selection transistor Tsl. The semiconductor layer <b>45</b> forms the initializing transistor Tint and is extended in the x direction while facing the semiconductor layer <b>32</b> across the semiconductor layer <b>42</b>.

0104The surface of the substrate <b>10</b> on which the above-described components are formed is covered with the gate insulating layer L<b>0</b>. As shown in <figref idref="DRAWINGS">FIG. 14</figref>, the first data line portion <b>131</b>, the selection line <b>11</b>, the initializing line <b>12</b>, the intermediate conductor <b>52</b>, and a first relay wiring pattern <b>171</b> are formed from the same layer on the surface of the gate insulating layer L<b>0</b>. As in the first embodiment, the first data line portion <b>131</b> forms the data line <b>13</b>, and is extended in the Y direction and is located farther toward the positive side in the x direction than the intermediate conductor <b>52</b>.

0105The initializing line <b>12</b> includes a first gate electrode <b>121</b> and a second gate electrode <b>122</b> which are branched from the midpoint portion of the initializing line <b>12</b> toward the negative side of the Y direction and which are overlapped with the semiconductor layer <b>45</b>. The areas of the semiconductor layer <b>45</b> that are overlapped with the first gate electrode <b>121</b> and the second gate electrode <b>122</b> serve as the channel region of the initializing transistor Tint. Similarly, the selection line <b>11</b> includes a first gate electrode <b>111</b> and a second gate electrode <b>112</b> which are branched from the midpoint portion of the selection line <b>11</b> toward the negative side in the Y direction and which are overlapped with the element portion <b>421</b> of the semiconductor layer <b>42</b>. The first gate electrode <b>111</b> and the second gate electrode <b>112</b> are located adjacent to each other in the x direction with a gap therebetween. The areas of the element portion <b>421</b> that are overlapped with the first gate electrode <b>111</b> and the second gate electrode <b>112</b> across the gate insulating layer L<b>0</b> serve as the channel region of the selection transistor Tsl. Accordingly, the selection transistor Tsl and the initializing transistor Tint are dual-gate-structured thin-film transistors.

0106The intermediate conductor <b>52</b> includes an electrode E<b>1</b> that forms the capacitor element C<b>1</b> while facing an electrode E<b>2</b>, a gate electrode <b>521</b> extending from the electrode E<b>1</b> toward the negative side in the Y direction, and a connecting portion <b>523</b> projecting from substantially the central portion of the electrode E<b>1</b> toward the positive side in the Y direction. The gate electrode <b>521</b> is extended in the Y direction such that it is overlapped with the entire width of the semiconductor layer <b>32</b> in the Y direction. As shown in <figref idref="DRAWINGS">FIG. 14</figref>, the area of the semiconductor layer <b>32</b> that faces the gate electrode <b>521</b> across the gate insulating layer L<b>0</b> serves as a channel region <b>32</b><i>c </i>of the drive transistor Tdr. A drain region <b>32</b><i>d </i>and a source region <b>32</b><i>s </i>are respectively disposed toward the negative side and the positive side in the x direction across the channel region <b>32</b><i>c. </i>

0107The first relay wiring pattern <b>171</b> is a wiring pattern for electrically connecting the initializing transistor Tint with the drain region <b>32</b><i>d </i>of the drive transistor Tdr (such a wiring pattern is hereinafter referred to as a “relay wiring pattern”), and is extended in the Y direction and is located farther toward the negative side in the x direction than the intermediate conductor <b>52</b>. That is, in this embodiment, the intermediate conductor <b>52</b> is disposed in the gap between the first data line portion <b>131</b> and the first relay wiring pattern <b>171</b>.

0108The surface of the gate insulating layer L<b>0</b> on which the above-described components are formed is covered with the first insulating layer L<b>1</b>. As shown in <figref idref="DRAWINGS">FIGS. 12 and 15</figref>, the second data line portion <b>132</b>, a connecting portion <b>62</b>, a second relay wiring pattern <b>172</b>, an electrical continuity portion <b>72</b>, and the power supply line <b>15</b> are formed on the surface of the first insulating layer L<b>1</b>.

0109As in the first embodiment, the second data line portion <b>132</b> forms, together with the first data line portion <b>131</b>, the data line <b>13</b>. The second data line portion <b>132</b> is extended in the Y direction from the end <b>132</b><i>a </i>which is electrically connected to the top end <b>131</b><i>a </i>(see <figref idref="DRAWINGS">FIG. 14</figref>) of the first data line portion <b>131</b> through a contact hole Hb<b>1</b> to the end <b>132</b><i>b</i>. The end <b>132</b><i>b </i>is electrically connected to the bottom end <b>131</b><i>b </i>(see <figref idref="DRAWINGS">FIG. 14</figref>) of the first data line portion <b>131</b> through a contact hole Hb<b>2</b>. The second data line portion <b>132</b> is electrically connected to the end of the element portion <b>421</b> through a contact hole Hb<b>3</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b>. That is, the data line <b>13</b> and the selection transistor Tsl are electrically connected to each other through the contact hole Hb<b>3</b>.

0110The connecting portion <b>62</b> is extended, as shown in <figref idref="DRAWINGS">FIGS. 14 and 15</figref>, in the Y direction such that it is overlapped with the connecting portion <b>523</b> of the intermediate conductor <b>52</b> and an end <b>451</b> of the semiconductor layer <b>45</b> located at the positive side in the x direction. The connecting portion <b>62</b> is electrically connected to the connecting portion <b>523</b> (electrode E<b>1</b> and gate electrode <b>521</b>) through a contact hole Hb<b>4</b> passing through the first insulating layer L<b>1</b>, and is also connected to the end <b>451</b> of the semiconductor layer <b>45</b> through a contact hole Hb<b>5</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b>. That is, the electrode E<b>1</b> of the capacitor element C<b>1</b> (and the gate electrode <b>521</b> of the drive transistor Tdr) and the initializing transistor Tint are electrically connected to each other through the connecting portion <b>62</b>.

0111When viewed perpendicularly to the substrate <b>10</b>, as shown in <figref idref="DRAWINGS">FIG. 15</figref>, the connecting portion <b>62</b> is located in the gap between the first gate electrode <b>111</b> and the second gate electrode <b>112</b> of the selection transistor Tsl. Accordingly, the connecting portion <b>62</b> is not overlapped with the first gate electrode <b>111</b> or the second gate electrode <b>112</b>. If the connecting portion <b>62</b> is overlapped with the first gate electrode <b>111</b> (or the second gate electrode <b>112</b>), capacitive coupled is established therebetween. Accordingly, due to a change in the potential of the connecting portion <b>62</b> (i.e., the potential of the electrode E<b>1</b> and the potential of the gate electrode <b>511</b> of the drive transistor Tdr), the potential of the first gate electrode <b>111</b> is also changed, thereby encouraging the occurrence of blunt waves in the initializing signal Sb. As a result, a delay may be caused in the operation of the initializing transistor Tint.

0112In this embodiment, however, since the connecting portion <b>62</b> is formed such that it is not overlapped with the first gate electrode <b>111</b> or the second gate electrode <b>112</b>, the capacitive coupling therebetween can be suppressed. Accordingly, the influence on the initializing transistor Tint by a change in the potential of the connecting portion <b>62</b> is reduced, and as a result, the fast operation of the initializing transistor Tint can be achieved.

0113As described above, the initializing transistor Tint and the electrode E<b>1</b> of the capacitor element C<b>1</b> are electrically connected to each other through the connecting portion <b>62</b>. With this configuration, sufficient channel lengths can be ensured for the selection transistor Tsl and the initializing transistor Tint, and leakage of the current in the selection transistor Tsl or the initializing transistor Tint can be suppressed compared with the configuration with restricted channel lengths. Since the selection transistor Tsl and the initializing transistor Tint are connected to the gate electrode <b>521</b> of the drive transistor Tdr, fluctuations in the potential of the gate electrode <b>521</b> during the driving period caused by reduced leakage can be suppressed. Accordingly, in this embodiment, it is possible to maintain desired values of the light quantities of the light-emitting elements E with high precision.

0114As in the electrical continuity portion <b>71</b> of the first embodiment, the electrical continuity portion <b>72</b> shown in <figref idref="DRAWINGS">FIG. 15</figref> is disposed between the drain electrode of the drive transistor Tdr and the first electrode <b>21</b> of the light-emitting element E so that it can electrically connect them. The electrical continuity portion <b>72</b> is configured (substantially in an L shape) such that a part <b>721</b> extending in the Y direction is continuously formed with a part <b>722</b> located opposite the capacitor element C<b>1</b> across the drive transistor Tdr. The part <b>721</b> is overlapped with a top end <b>171</b><i>a </i>(see <figref idref="DRAWINGS">FIG. 14</figref>) of the first relay wiring pattern <b>171</b> and the drain region <b>32</b><i>d </i>of the semiconductor layer <b>32</b>. The part <b>721</b> is electrically connected to the top end <b>171</b><i>a </i>through a contact hole Hb<b>6</b> passing through the first insulating layer L<b>1</b>.

0115In the area of the first insulating layer L<b>1</b> that is overlapped with the drain region <b>32</b><i>d</i>, a plurality of (in this case, two) contact holes Hb<b>7</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b> are formed. The contact holes Hb<b>7</b> are disposed in the Y direction in which the gate electrode <b>521</b> is extended (i.e., along the channel width of the drive transistor Tdr). The part <b>721</b> of the electrical continuity portion <b>72</b> is electrically connected to the drain region <b>32</b><i>d </i>through the contact holes Hb<b>7</b>.

0116The second relay wiring pattern <b>172</b> is extended, as shown in <figref idref="DRAWINGS">FIGS. 14 and 15</figref>, in the Y direction such that it is overlapped with the first relay wiring pattern <b>171</b> and an end <b>452</b> of the semiconductor layer <b>45</b> located at the negative side in the x direction. The second relay wiring pattern <b>172</b> is electrically connected to the end <b>452</b> through a contact hole Hb<b>8</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b>, and is also connected to a bottom end <b>171</b><i>b </i>of the first relay wiring pattern <b>171</b> through a contact hole Hb<b>9</b> passing through the first insulating layer L<b>1</b>. In this manner, the initializing transistor Tint and the drain region <b>32</b><i>d </i>of the drive transistor Tdr (and the electrical continuity portion <b>72</b>) are electrically connected to each other through a relay wiring pattern <b>17</b> formed by the first relay wiring pattern <b>171</b> and the second relay wiring pattern <b>172</b>.

0117<figref idref="DRAWINGS">FIG. 16</figref> is a plan view illustrating the four unit elements P that are in the processing step shown in <figref idref="DRAWINGS">FIG. 15</figref> and disposed in the x direction and in the Y direction. The power supply line <b>15</b> of this embodiment is configured, as shown in <figref idref="DRAWINGS">FIGS. 15 and 16</figref>, such that a first portion <b>151</b> extending in the x direction over a plurality of unit elements P and a second portion <b>152</b> extending in the Y direction over a plurality of unit elements P cross each other (in a lattice-like form).

0118In the area of the first insulating layer L<b>1</b> that is overlapped with the source region <b>32</b><i>s </i>of the semiconductor layer <b>32</b>, as shown in <figref idref="DRAWINGS">FIG. 15</figref>, a plurality of (in this case, two) contact holes Hb<b>10</b> passing through the first insulating layer L<b>1</b> and the gate insulating layer L<b>0</b> are formed. The contact holes Hb<b>10</b> are disposed in the Y direction in which the gate electrode <b>521</b> is extended. The power supply line <b>15</b> (second portion <b>152</b>) is electrically connected to the source region <b>32</b><i>s </i>through the contact holes Hb<b>10</b>.

0119The first portion <b>151</b> is extended in the x direction such that it passes through the gap between the second data line portions <b>132</b> and the gap between the second relay wiring pattern <b>172</b> and the electrical continuity portion <b>72</b> (part <b>721</b>). Accordingly, when viewed perpendicularly to the substrate <b>10</b>, as shown in <figref idref="DRAWINGS">FIGS. 15 and 16</figref>, the first portion <b>151</b> is overlapped with the first data line portion <b>131</b>, the first relay wiring pattern <b>171</b>, and the capacitor element C<b>1</b>. The second portion <b>152</b> is extended in the Y direction such that it passes through the gap between the electrical continuity portion <b>72</b> (part <b>722</b>) and the second data line portion <b>132</b> and the gap between the connecting portion <b>62</b> and the second data line portion <b>132</b>. As shown in <figref idref="DRAWINGS">FIGS. 15 and 16</figref>, the power supply line <b>15</b> is not overlapped with the selection transistor Tsl or the initializing transistor Tint.

0120The entire surface of the first insulating layer L<b>1</b> on which the above-described elements are formed is covered with the second insulating layer L<b>2</b>. The light-emitting elements E and the barriers <b>25</b> that partition the gaps between the light-emitting elements E are formed, as shown in <figref idref="DRAWINGS">FIG. 12</figref>, on the surface of the second insulating layer L<b>2</b>. As in the first embodiment, the part <b>722</b> of the electrical continuity portion <b>72</b> is electrically connected to the first electrode <b>21</b> through a contact hole Hb<b>11</b> passing through the second insulating layer L<b>2</b>. The specific configurations of the light-emitting element E and the barrier <b>25</b> are similar to those of the first embodiment,

0121As discussed above, in this embodiment, the electrical continuity portion <b>72</b> is disposed opposite the capacitor element C<b>1</b> across the drive transistor Tdr. Accordingly, as in the first embodiment, the parasitic capacitance (capacitance Cx shown in <figref idref="DRAWINGS">FIG. 11</figref>) formed between the electrode E<b>1</b> and the electrical continuity portion <b>72</b> is reduced. As a result, the capacitance of the capacitor element C<b>1</b> can be reduced. Additionally, since the power supply line <b>15</b> is formed such that it is not overlapped with the selection transistor Tsl or the initializing transistor Tint. Accordingly, as in the first embodiment, it is possible to achieve a fast operation of the selection transistor Tsl and the initializing transistor Tint with desired timings.

0122In this embodiment, the electrical continuity portion <b>72</b>, the connecting portion <b>62</b>, and the second relay wiring pattern <b>172</b> are formed from the same layer as that of the power supply line <b>15</b>. Also, the electrical continuity portion <b>72</b> is disposed farther toward the negative side in the Y direction than the drive transistor Tdr (i.e., on one side along the width of the power supply line <b>15</b>), and the connecting portion <b>62</b> and the second relay wiring pattern <b>172</b> are disposed opposite the electrical continuity portion <b>72</b> (i.e., on the other side along the width of the power supply line <b>15</b>). Accordingly, a sufficient space can be formed for the first portion <b>151</b> of the power supply line <b>15</b> extending in the x direction in the gap between the electrical continuity portion <b>72</b> and the connecting portion <b>62</b> (second relay wiring pattern <b>172</b>). Additionally, the space that is overlapped with the capacitor element C<b>1</b> when viewed perpendicularly to the substrate <b>10</b> can be utilized for the power supply line <b>15</b>. Thus, as in the first embodiment, the power supply line <b>15</b> (first portion <b>151</b>) can be formed to be wide so that the resistance of the power supply line <b>15</b> can be reduced.

0123In this embodiment, since the first portions <b>151</b> can be interconnected to each other by the second portions <b>152</b> extending in the Y direction, the resistance of the power supply line <b>15</b> can further be reduced compared with the configuration in which the power supply line <b>15</b> is formed of only the first portions <b>151</b>. Additionally, since the first portion <b>151</b> of the power supply line <b>15</b> is formed in a simple shape, such as a bar-like shape, a break or damage in the power supply line <b>15</b> can be suppressed compared with the configuration in which the power supply line <b>15</b> is formed in a complicated shape so that it can avoid the components (electrical continuity portion <b>72</b> and connecting portion <b>62</b>) formed from the same layer as that of the power supply line <b>15</b>.

0124In this embodiment, in each unit element P, the data line <b>13</b> is extended along the periphery toward the positive side in the x direction, and the relay wiring pattern <b>17</b> is extended along the periphery toward the negative side in the x direction. With this configuration, when focusing on one unit element P<b>1</b> and a unit element P<b>2</b> adjacently located toward the negative side in the x direction, as shown in <figref idref="DRAWINGS">FIG. 16</figref>, the relay wiring pattern <b>17</b> of the unit element P<b>1</b> intervenes between the capacitor element C<b>1</b> of the unit element P<b>1</b> and the data line <b>13</b> corresponding to the unit element P<b>2</b>. Accordingly, the capacitance formed between the capacitor element C<b>1</b> of the unit element P<b>1</b> and the data line <b>13</b> of the unit element P<b>2</b> can be reduced compared with the configuration of the first embodiment in which the capacitor element C<b>1</b> of one unit element P is located in proximity with the data line <b>13</b> of the adjacent unit element P. With this configuration, the influence on the capacitor element C<b>1</b> of the unit element P<b>1</b> by a change in the potential of the data line <b>13</b> of the unit element P<b>2</b> can be suppressed. As a result, the gate potential Vg of the drive transistor Tdr of each unit element P and the light quantity of the light-emitting element E corresponding to the gate potential Vg can be set to desired values with high precision.

Modified Examples of Second Embodiment

0125A modified example of the above-described second embodiment is as follows. <figref idref="DRAWINGS">FIG. 17</figref> is a plan view illustrating the unit element P in the processing step shown in <figref idref="DRAWINGS">FIG. 14</figref> in which the first insulating layer L<b>1</b> is formed. In the second embodiment, the gate electrode <b>521</b> of the drive transistor Tdr is extended in the Y direction. In this modified example, however, as shown in <figref idref="DRAWINGS">FIG. 17</figref>, the gate electrode <b>521</b> of the drive transistor Tdr is extended in the x direction. In this modified example, elements similar to those of the second embodiment are designated with like reference numerals, and an explanation thereof is thus omitted.

0126The intermediate conductor <b>52</b> of this modified example includes an interconnecting portion <b>525</b> extending from the top left of the electrode E<b>1</b> toward the negative side in the Y direction and the gate electrode <b>521</b> which extends in the x direction from interconnecting portion <b>525</b> and which is overlapped with the semiconductor layer <b>32</b>. The gate electrode <b>521</b> is overlapped with the entire width of the semiconductor layer <b>32</b> in the x direction. The area of the semiconductor layer <b>32</b> that faces the gate electrode <b>521</b> across the gate insulating layer L<b>0</b> serves as the channel region <b>32</b><i>c </i>of the semiconductor layer <b>32</b>. The drain region <b>32</b><i>d </i>and the source region <b>32</b><i>s </i>are respectively disposed toward the negative side and the positive side in the Y direction across the channel region <b>32</b><i>c. </i>

0127<figref idref="DRAWINGS">FIG. 18</figref> is a plan view illustrating the unit element P in the processing step shown in <figref idref="DRAWINGS">FIG. 15</figref> in which the power supply line <b>15</b> and the electrical continuity portion <b>72</b> are formed. The electrical continuity portion <b>72</b> is formed, as shown in <figref idref="DRAWINGS">FIG. 18</figref>, substantially in a rectangular shape in the area opposite the capacitor element C<b>1</b> across the drive transistor Tdr. As shown in <figref idref="DRAWINGS">FIGS. 17 and 18</figref>, the electrical continuity portion <b>72</b> is electrically connected to the drain region <b>32</b><i>d </i>through the plurality of contact holes Hb<b>7</b> disposed in the x direction in which the gate electrode <b>521</b> is extended (i.e., in the direction along the channel width of the drive transistor Tdr). The power supply line <b>15</b> is electrically connected to the source region <b>32</b><i>s </i>through the plurality of contact holes Hb<b>10</b> disposed in the x direction in which the gate electrode <b>521</b> is extended.

0128As described above, since the gate electrode <b>521</b> of the drive transistor Tdr is extended in the x direction, the drain region <b>32</b><i>d </i>is formed in an elongated shape in the x direction in the area opposite the capacitor element C<b>1</b> across the gate electrode <b>521</b>. With this configuration, it is not necessary to form a portion (part <b>721</b> in the first embodiment) extending in the Y direction along the drive transistor Tdr for the electrical continuity portion <b>72</b>. Thus, according to this modified example, as is seen from comparison of <figref idref="DRAWINGS">FIG. 18</figref> with <figref idref="DRAWINGS">FIG. 15</figref>, the first portion <b>151</b> of the power supply line <b>15</b> extending along the gate electrode <b>521</b> can be formed to be wider than that of the second embodiment.

0129In this modified example, the contact holes Hb<b>7</b>, the contact hole Hb<b>6</b> (the continuity portion between the relay wiring pattern <b>17</b> and the electrical continuity portion <b>72</b>), and the contact hole Hb<b>1</b> (the continuity portion between the first data line portion <b>131</b> and the second data line portion <b>132</b>) are disposed linearly in the x direction. Accordingly, a sufficient line width of the first portion <b>151</b> extending linearly (in a bar-like shape) in the x direction can be ensured compared with the configuration in which the contact holes Hb<b>7</b>, Hb<b>6</b> and Hb<b>1</b> are displaced from each other in the x direction.

0130In the second embodiment, the gate electrode <b>521</b> is extended in the direction orthogonal to the first portion <b>151</b> of the power supply line <b>15</b>. Accordingly, as the length of the gate electrode <b>521</b> (strictly speaking, the length of the part <b>721</b> of the electrical continuity portion <b>72</b>) becomes longer, the line width of the first portion <b>151</b> becomes smaller. In contrast, in this modified example, since the gate electrode <b>521</b> is extended in parallel with the first portion <b>151</b>, the length of the gate electrode <b>521</b> can be increased without reducing the line width of the first portion <b>151</b>. The length of the gate electrode <b>521</b> corresponds to the channel width of the drive transistor Tdr. Accordingly, the channel width of the drive transistor Tdr can be increased while maintaining the line width of the first portion <b>151</b>. It is thus possible to ensure a sufficient current to be supplied to the light-emitting element E from the power supply line <b>15</b> via the drive transistor Tdr having a large channel width.

MODIFIED EXAMPLES

0131Various modifications can be made to the above-described embodiments. Specific modified examples are as follows. The following modified examples may be combined if necessary.

First Modified Example

0132The electrical configuration of the unit elements P in the above-described embodiments may be changed if necessary. Examples of the specific mode of the unit element P that are applicable to the invention are as follows.

0133A light-emission control transistor Tent may be inserted, as shown in <figref idref="DRAWINGS">FIG. 19</figref>, between the drive transistor Tdr and the light-emitting element E. The light-emission control transistor Tent is a switching element for controlling the electrical connection between the drain electrode of the drive transistor Tdr and the first electrode <b>21</b> of the light-emitting element E in accordance with a light-emission control signal Sc supplied to a light-emission control line <b>14</b>. When the light-emission control transistor Tent is turned ON, a current path from the power supply line <b>15</b> to the light-emitting element E is formed to allow the light-emitting element E to emit light. When the light-emission control transistor Tent is turned OFF, the current path is disconnected to prohibit the light-emitting element E from emitting light. With this configuration, therefore, in the period other than the initializing period and the writing period, i.e., only in the driving period, the light-emission control transistor Tent is turned ON to allow the light-emitting element E to emit light. Accordingly, the period during which the light-emitting element E emits light can be precisely set.

0134In this modified example, the light-emission control transistor Tent is disposed opposite the capacitor element C<b>1</b> across the drive transistor Tdr (i.e., toward the negative side in the Y direction). According to this configuration, the power supply line <b>15</b> can be formed to be wider such that it is overlapped with the drive transistor Tdr and the capacitor element C<b>1</b> compared with the configuration in which the light-emission control transistor Tent is disposed in the gap between the drive transistor Tdr and the capacitor element C<b>1</b>.

0135A capacitor element C<b>2</b> may be inserted, as shown in <figref idref="DRAWINGS">FIG. 20</figref>, between the gate electrode and the source electrode (power supply line <b>15</b>) of the drive transistor Tdr. With this configuration, the gate potential Vg of the drive transistor Tdr set in the writing period can be held in the capacitor element C<b>2</b> during the driving period. However, if the area of the gate electrode (area of the channel region) of the drive transistor Tdr is sufficiently large, the gate potential Vg can be held in the gate capacitor of the drive transistor Tdr. In this case, the gate potential Vg can be held during the driving period even if the capacitor element C<b>2</b> is not disposed as in the first and second embodiments.

0136The unit element P shown in <figref idref="DRAWINGS">FIG. 21</figref> may be also be used. In this unit element P, the electrical connection between the gate electrode of the drive transistor Tdr and the data line <b>13</b> is controlled by the selection transistor Tsl without forming the capacitor element C<b>1</b> and the initializing transistor Tint (initializing line <b>12</b>). The capacitor C<b>2</b> is interposed between the gate electrode and the source electrode (power supply line <b>15</b>) of the drive transistor Tdr.

0137With this configuration, when the selection transistor Tsl is turned ON, the data potential Vdata corresponding to the grayscale level specified by the light-emitting element E is supplied to the gate electrode of the drive transistor Tdr from the data line <b>13</b> via the selection transistor Tsl. In this case, since electric charge corresponding to the data potential Vdata is stored in the capacitor element C<b>2</b>, the gate potential Vg of the drive transistor Tdr can be maintained at the data potential Vdata even if the selection transistor Ts is turned OFF. Accordingly, the current corresponding to the gate potential Vg of the drive transistor Tdr (i.e., the current corresponding to the data potential Vdata) can be continuously supplied to the light-emitting element E. Then, the light-emitting element E emits light with the luminance corresponding to the data potential Vdata.

0138The capacitor element C<b>2</b> shown in <figref idref="DRAWINGS">FIG. 21</figref> is disposed on the surface of the substrate <b>10</b> in a manner similar to the capacitor element C<b>1</b>. In this modified example, advantages similar to those of the first or second embodiment can be achieved. As described above, the capacitor element connected to the gate electrode of the drive transistor Tdr may be the capacitor element C<b>1</b> for setting the gate potential Vg of the drive transistor Tdr by capacitive coupling or the capacitor element C<b>2</b> for holding the data potential Vdata supplied to the gate electrode of the drive transistor Tdr from the data line <b>13</b>.

Second Modified Example

0139In the above-described embodiments and modified examples, the first electrode <b>21</b> is composed of a light-reflective material. Alternatively, light emitted from the light-emitting layer <b>23</b> toward the substrate <b>10</b> may be reflected by a reflective layer different from the first electrode <b>21</b> and may be output to the side opposite the substrate <b>10</b>. In this configuration, a reflective layer is formed on the surface of the first insulating layer L<b>1</b> by a light-reflective material, and the first electrode <b>21</b> is formed such that it covers the reflective layer. In this case, the first electrode <b>21</b> is composed of a light-transmissive, conductive material, such as ITO or IZO. In the above-described embodiments, the second electrode <b>22</b> is composed of a light-transmissive material. Alternatively, it may be formed of a light-shielding or light-reflective, conductive material and formed to be sufficiently thin. In this case, light emitted from the light-emitting layer <b>23</b> can pass through the second electrode <b>22</b>.

0140The invention is also applicable to a bottom-emission-type light-emitting device in which light emitted from the light-emitting layer <b>23</b> passes through the substrate <b>10</b> and is output. In this configuration, the second electrode <b>22</b> is composed of a light-reflective, conductive material, and also, the first electrode <b>21</b> is composed of a light-transmissive, conductive material. Then, light emitted from the light-emitting layer <b>23</b> toward the substrate <b>10</b> and light emitted from the light-emitting layer <b>23</b> toward the side opposite the substrate <b>10</b> and reflected on the surface of the second electrode <b>22</b> pass through the first electrode <b>21</b> and the substrate <b>10</b> and are output.

Third Modified Example

0141In the first and second embodiments the power supply line <b>15</b> is not overlapped with the selection transistor Tsl or the initializing transistor Tint. However, it may be overlapped with the selection transistor Tsl or the initializing transistor Tint.

Fourth Modified Example

0142In the second embodiment, the connecting portion <b>62</b> is formed in the gap between the first gate electrode <b>111</b> and the second gate electrode <b>112</b> of the selection transistor Tsl. Similarly, the second portion <b>152</b> of the power supply line <b>15</b> may be formed in the gap between the first gate electrode <b>121</b> and the second gate electrode <b>122</b> of the initializing transistor Tint.

Fifth Modified Example

0143In the first embodiment, the power supply line <b>15</b> includes only a portion extending in the x direction (corresponding to the first portion <b>151</b>). However, as in the second embodiment, the power supply line <b>15</b> may also include a portion extending in the Y direction to interconnect the first portions <b>151</b> (corresponding to the second portion <b>152</b>). The second portion <b>152</b> is extended in the Y direction in the gap between the connecting portion <b>61</b> and the electrical continuity portion <b>71</b> shown in <figref idref="DRAWINGS">FIG. 7</figref> or the gap between the adjacent unit elements P, and interconnects the power supply lines <b>15</b> (first portions <b>151</b>) located adjacent to each other in the Y direction. With this configuration, the resistance of the power supply line <b>15</b> can further be reduced compared with the first embodiment.

Sixth Modified Example

0144In the above-described embodiments, the light-emitting layer <b>23</b> is formed only in the inner periphery of the barrier <b>25</b>. Alternatively, the light-emitting layer <b>23</b> may be formed continuously on the entire surface of the substrate <b>10</b> (and more specifically, on the entire surface of the second insulating layer L<b>2</b>). With this configuration, a less expensive film-forming technique, such as spin coating, may be employed for forming the light-emitting layer <b>23</b>. The first electrode <b>21</b> is formed for each light-emitting element E. Accordingly, even though the light-emitting layer <b>23</b> is continuously formed over the plurality of light-emitting elements E, the light quantity of the light-emitting layer <b>23</b> can be controlled for each light-emitting element E. In the configuration in which the light-emitting layer <b>23</b> is continuously formed over the plurality of light-emitting elements E, the provision of the barriers <b>25</b> can be omitted.

0145If an ink-jet method (droplet discharge method) in which droplets of a light-emitting material are discharged to each space partitioned by the barriers <b>25</b> is employed for forming the light-emitting layer <b>23</b>, it is preferable that the barriers <b>25</b> be formed on the surface of the second insulating layer L<b>2</b>, as in the first and second embodiments. The method for forming the light-emitting layer <b>23</b> for each light-emitting element E can be changed according to the necessity. More specifically, a light-emitting-material film member formed on the entire surface of the substrate <b>10</b> may be selectively removed, or various patterning techniques, such as a laser transfer (laser-induced thermal imaging (LTIT) method, may be employed. In this case, the light-emitting layer <b>23</b> can be formed for each light-emitting element E without the need to form the barriers <b>25</b>. As described above, the barriers <b>25</b> are not essential for the light-emitting device.

Seventh Modified Example

0146In the foregoing embodiments, the light-emitting element E includes the light-emitting layer <b>23</b> composed of an organic EL material. However, the light-emitting element E is not restricted to this type. For example, a light-emitting element including a light-emitting layer composed of an inorganic EL material or a light-emitting diode (LED) may be employed. That is, the specific structure or material of the light-emitting element is not restricted as long as the light-emitting element emits light by the supply of electric energy (typically, the supply of a current).

Applied Examples

0147Specific examples of electronic apparatuses utilizing the light-emitting device of an embodiment of the invention are described below. <figref idref="DRAWINGS">FIG. 22</figref> is a perspective view illustrating the configuration of a mobile personal computer <b>2000</b> using one of the above-described light-emitting devices D. The personal computer <b>2000</b> includes one of the light-emitting devices D as a display unit and a main unit <b>2010</b>. The main unit <b>2010</b> includes a power switch <b>2001</b> and a keyboard <b>2002</b>. In this light-emitting device D, since the light-emitting layer <b>23</b> composed of an organic EL material is used, a screen having a wide viewing angle can be provided.

0148<figref idref="DRAWINGS">FIG. 23</figref> illustrates the configuration of a cellular telephone <b>3000</b> utilizing one of the light-emitting devices D. The cellular telephone <b>3000</b> includes a plurality of operation buttons <b>3001</b>, scroll buttons <b>3002</b>, and the light-emitting device D. The scroll buttons <b>3002</b> are operated so that the screen displayed on the light-emitting device D can be scrolled.

0149<figref idref="DRAWINGS">FIG. 24</figref> illustrates the configuration of a portable information terminal <b>4000</b> (personal digital assistants PDA) utilizing one of the light-emitting devices D. The portable information terminal <b>4000</b> includes a plurality of operation buttons <b>4001</b>, a power switch <b>4002</b>, and the light-emitting device D as a display unit. When the power switch <b>4002</b> is operated, various items of information, such as an address book and a diary, can be displayed on the light-emitting device D.

0150The electronic apparatuses utilizing a light-emitting device of an embodiment of the invention may include, not only the apparatuses shown in <figref idref="DRAWINGS">FIGS. 22 through 24</figref>, but also digital still cameras, televisions, video cameras, car navigation systems, pagers, electronic diaries, electronic paper, calculators, word-processors, workstations, videophones, point-of-sale (POS) terminals, printers, scanners, copying machines, video players, and touch panels. The purpose of the light-emitting device of an embodiment of the invention is not restricted to the display of images. For example, in an image forming apparatus, such as a photo-writing printer or an electronic copying machine, a write head that exposes light to a photosensitive member in accordance with an image to be formed on a recording material, such as paper, is used. The light-emitting device of an embodiment of the invention can be used as this type of write head.